Anecdote: a company I used to work for was growing rapidly by acquisition, which ended up being the motivation to go ipv6 internally. With IPv4 every new compan

Anecdote: a company I used to work for was growing rapidly by acquisition, which ended up being the motivation to go ipv6 internally. With IPv4 every new company was basically guaranteed to have an internal network that conflicted with one of our existing subnets, so we either had to re-ip them, which was brutal or put crazy NATs on our VPNs alongside dns insanity. Going IPv6 meant that getting them on our mesh was simple. Just enable IPv6 on their network (which was far easier than most network admins fear it will be), then join their IPv6 network to the mesh, let their IPv4 be whatever it was. Update all DNS servers to have AAAA records. No more conflicts!